Carex magellanica is one of the bipolar disjunct species of Carex discussed by D. M. Moore and A. O. Chater (1971). Carex magellanica subsp. magellanica occurs in cool temperate regions of South America. It is distinguished from C. magellanica subsp. irrigua by the terminal spike being almost always gynecandrous, the lateral spikes with (2–)3–7 staminate flowers, and the pistillate scales (1.3–)1.6–2.3 mm wide.